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TimerApp/NativeMethods.cs
2026-01-17 12:48:01 +08:00

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C#
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using System;
using System.Runtime.InteropServices;
namespace TimerApp
{
public static class NativeMethods
{
[StructLayout(LayoutKind.Sequential)]
struct LASTINPUTINFO
{
public static readonly int SizeOf = Marshal.SizeOf(typeof(LASTINPUTINFO));
[MarshalAs(UnmanagedType.U4)]
public UInt32 cbSize;
[MarshalAs(UnmanagedType.U4)]
public UInt32 dwTime;
}
[DllImport("user32.dll")]
static extern bool GetLastInputInfo(ref LASTINPUTINFO plii);
/// <summary>
/// 获取系统空闲时间(毫秒)
/// </summary>
/// <returns></returns>
public static long GetIdleTime()
{
LASTINPUTINFO lastInputInfo = new LASTINPUTINFO();
lastInputInfo.cbSize = (uint)Marshal.SizeOf(lastInputInfo);
lastInputInfo.dwTime = 0;
if (GetLastInputInfo(ref lastInputInfo))
{
// Environment.TickCount 可能会在大约 24.9 天后翻转为负数,
// 但 GetLastInputInfo 返回的也是 uint (DWORD),所以我们统一转为 long 处理差值
// 或者直接使用 unchecked 减法处理溢出
// 更稳健的做法是使用 GetTickCount64 (Vista+),但 Environment.TickCount 在 .NET Core 3.1+ 已经是 64位了(Environment.TickCount64)
// 这里为了兼容性,我们简单处理。注意 GetLastInputInfo 返回的是 uint 毫秒数。
long envTicks = Environment.TickCount;
// 处理 TickCount 翻转问题 (Environment.TickCount 是 intGetLastInputInfo 是 uint)
// 简单的做法:
return (long)GetTickCount() - (long)lastInputInfo.dwTime;
}
return 0;
}
[DllImport("kernel32.dll")]
static extern uint GetTickCount();
}
}